The present application is a follow-up of a European Patent Application filed by the same applicant on Dec. 2, 2008, of which number is EP08170468.6 and of which title is “A surveillance system comprising a radar antenna mounted on a blade of a windmill,” which is incorporated by reference herein. It is hereunder referenced to as “the previous application”. Basically, the previous application describes a surveillance system for detecting targets, the system including a Synthetic Aperture Radar (SAR) antenna mounted on a blade of a windmill. In particular, such an arrangement allows for estimation of cross-range between targets with high resolution when the blade rotates. However, a drawback of such an arrangement is that the SAR capability is not operational in the absence of wind or when the wind is not strong enough to drive the blade in rotation, hereby preventing high cross-range resolution.
Existing solutions based on stationary radar antennas suggest enhancing the cross-range resolution between targets by means of a data fusion technique. For example, interferometry may achieve satisfactory results from several measurements varying in size.